Tool-holder.



C. GRUNBAUCH.

TOOL HOLDER.

APPLICATION FILED APR. 28. 1913. RENEWED FEB. 15.1915- Patented Sept.21, 1915.

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CHARLES GEUNBAUCII,

0F DETROIT, MICHIGAN, ASSIGNOR OF ONE-HALF T0 NELSON J SEAVER, OFDETROIT, MICHIGAN.

TOOL-HOLDER.

1,15%,Olll.

Application filed April 28, 1913, Serial No. 764,106.

To (ZZZ whom it may concern Be it known that I, CHARLES GRUNBAUCH,

a citizen of the United Eltates of America,

residing at Detroit, in the county ofWVayne and State of Michigan, haveinvented certain new and useful Improvements in Tool- Holders, of whichthe following is a specification, reference being had therein to theaccompanying drawings.

My invention relates to tool holders and has among the objects thereofto provide a construction in which the die-head during the operationthereof upon the work, is permitted to feed forward independent of theturret or die-head support; to provide means for )reventing binding ofrelatively movable parts during forward feeding of the die-head; andfurther to provide means for varying the forward travel of the die-head.

bther objects of the invention will more fully hereinafter appear.

The invention consists in the peculiar construction, arrangement andcombination of parts as will be hereinafter described and particularlypointed out in the claims.

In the drawings,i*igure 1 is a side elevation of a lathe embodying myinvention; and Figs. 2 and 3 illustrate certain details of construction;and Figs. 4t and 5 illustrate a modiiication.

A designates the bed of the machine. upon which is mounted a movablecarriage B, and G is a support or slide upon the carriage for the turretor die-head holcer I), the slide C being fed to the desired positi onthrough the medium of hand levers E in the' well-known manner. V

F is the spindle of the machine, adapted to receive the work, and beingdriven in any suitable manner.

The parts so far described are of standard construction.

With one type of turret lathe now in general use the die-head isconnected to the turret so that during the forward movement of thedie-head upon the work the turret is pulled along by the die-head.Because of the weight of the turret it quite frequentlyhappensespecially in turning threads upon membersthat the threads willbe damaged, due to the force required to pull the turret along. If anautomatically releasing diehead is employed, if the pulling stressbecomes too great the die-head will be partially opened, which will tendto strip or Specification of Letters Patent.

Renewed February 15, 1915. Serial No. 8,291.

otherwise injure the threads. With another type of turret lathe in quitecommon use, during the cutting operat1on-such as threading-the turret ispositively fed forward by suitable mechanism at a certain rate of speed.If the feeding of-the turret is not properly timed the threads will bedamaged, and considerable difficulty is quite fr quently occasioned inobtaining an accurate feeding of the turret. Devices have been employedwith lathes of the last-mentioned type to correct inaccuracies in theforward feeding of the turret, but they have not proven satisfactorywhere accurate threading or other cutting is required. To provide for anaccurate feeding of the die-head in relation to the work, I so connectthe diehead to theturret or other support that the head movesindependently of the support during the working operation and isentirely I free to feed forward properly.

In the drawings I have illustrated the invention as applied to a lathefor cutting threads upon rods, pipes or the like. Thus H is a sleevefitting an aperture or opening I of the turret and clamped in place inthe aperture through the medium of a set-screw J. This sleeve hasarranged therein the shank K of the die-head, the latter being hereinshown as of the automatically releasing type, the shank being free tomove within certain limits longitudinally within the sleeve. Turning ofthe shank within the sleeve is prevented by means of a shaft L carriedby the shank and having extensions L arranged in longitudinal slots I Jin the sleeve. Preferably the extensions L are provided with rollers M.

that a rod as N is to be threaded, the slide C is moved forwardlythrough the medium of the turnstile E until the dies 0 of the head Gengage the free end of the member N. In this position the rollers M areat the rear ends P of the slots. Further forward movement of the slidein relation to this support B is prevented by means of an adjustablescrew Q. The member D and sleeve II are therefore rigidly held againstforward movement. Upon the spindle being rotated, the threaded dies willcause the head G to be drawn forward until the rollers M contact withthe front ends R of the slots. This will arrest movement of the head Gand permit the die to be automati= cally released in the usual manner.As the tendency of the head G. during its forward movement is to rotate,if the slots in the sleeve were straight there would be considerablefriction between the rollers and the sides of the slots, which wouldtend to retard the forward feeding of the head. To overcome thisobjection I have so arranged the slots that a slight rotary movement ispermitted the head during the forward feeding thereof. Thus, one ofthe'slots extends at an angle to the longitudinal axis of the sleeve,while the other slot extends at an angle in the opposite direction, theslots in effect forming a spiral guide for the rollers M. Thus itisnecessary to hold the shank of the die-head against rotationsuiliciently to permit the die to cut the work, but if the friction ofthe rollers in the slots is too great the resistance to the forwardfeeding would strip the threads. On the other hand,

' if the slots were pitched too much, there would be a tendency to crowdthe die-head forward. This would make an imperfect thread. It isdesirable, therefore, to so pitch the slots that while sufficientresistance will be offered to the turning of the die-head to effect thecutting of the threads, nevertheless substantially no resistance isoffered to the forward feeding of the die-head. resistancebetweenthe'slots and rollers, as far as the forward feeding of thedie-head is concerned, approximates the angle'of friction. It will alsobe noted that the shank K and the member H are entirely free, except forthe pin and slot connection.

.The length of the thread may be varied by regulating the operativelength of the slots 1 J. lhis may be accomplished in any suitable mannerbut preferably a setscrew S is arranged at the rear end of each slot andhas the forward end thereof extending within the slot. By adjustingthese screws the operative relation of the slots may be varied.

In die-heads in which the work to be threaded projects through the head,the shank T is made hollow and provided with slots 1 J and the rollers Mare carried by stub shafts L uponthe sleeve D. The rear end of the shankhowever, solid and setscrews (4 b are carried thereby and have theirforward ends extending within the slots. 7

What I claim as my invention is:

1. The combination of a support held Copies of this patent may beobtained for five cents each, by addressing the Washington, D. C. i

The

against rotary and longitudinal movement,

telescopmg members, one of said members being connected to said supportagainst movement, a die-head carriedby the other member, and aconnection between said members permitting a free forward movement ofthe member carrying the die-head in a spiral path, the pitch ofthespiral path being proportioned in accordance with the stressestransmitted to the die-head to cause the resistance to the forwardfeeding of the die-head to approximate the angle of friction, for thepurpose described.

2. The. combination of a support held against rotary and longitudinalmovement, telescoping members, one of said members being connected tothe support againstmovement, a die-head carried by the other member, anda connection between said members permitting a free forward movement ofthe and rotarymovement, a die-head having a shank engaging said sleeve,and a connection between said shank and sleeve permitting a freelongitudinal travel of the shank within the sleeve in a spiral path,comprising diametrically opposedrollers upon the one, there being'spiral slots in the other within which said rollers are arranged, thepitch of the slots being proportioned in accordance with the stressestransmitted to the die-head to cause .the resistance to the forwardfeeding of the die-head to approximate the angle of friction, therebyavoiding binding of therollers within the slots during the workingoperation. 7 V l In testimony whereof I affix my signature in presenceof two witnesses. r I

V CHARLES GRUNBAUCH. VVitnes'ses:

NELSON J. SEAVER, WV M. J. BELKNAP.

Commissioner of Patents.

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